Ignition system



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IGNmon SYSTEM. y ARN-MATH FILD )UNE 5. 1913- RENEVIED VIAN. 20, 1920.

1,352,434 Patnwdsept. 14,1920.

wnuzsses: mvimon UNITED STATES PATENT OFFICE.

FRANK CONRAD, OF sWIssvALE, PENNSYLVANIA, AssIGNoR To wnsTINGHOUsE ELEC- Tmc AND MANUFACTURING COMPANY, A CORPORATION or PENNSYLVANIA.

IGNITION SYSTEM.

Specication of Letters Patent.

rai-@meu sem. i4. loco.

'Application led June 5, 19113, Serial No. 771,894. Renewed January 20. 1920. Serial No, 352,910.

To all whom. it may concern:

Be it known that I, FRANK CONRAD, a c1tizen of the United States. and a resident of Swissvale, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Ignition Systems, of which the following is n specification.

My invention relates to ignition systems that are adapted to supply current to the spark plugs of internal combustion engines or to other ignition devices.

The object .of my invention is to provide a system of' the character above indicated by means of which a more reliable and effective spark may be produced than is possible with the s stems 'heretofore provided.

In the operation of ignition systems employing spark plugs of the jump spark type, it is necessary to produce a current at high voltage to break down the resistance of the gap between the stationaryterminals of thc spark plugs.

Because of the high resistance of the ignition circuit, which usually comprises the. Y

secondary winding of a transformer, the amount of current which follows the initial discharge across the gap is usually so small that the spark is substantiall instantaneous and of low heat value and, t ierefore, is not etlicient for ignition purposes. It has been proposed to Connect the lowvoltage source of current'to the seconden' circuit for the purpose of securing a How of current from the source across the gap after the resistance of the gap has been lowered b v the hightension discharge. It has been found b v experiment that the How of current from the primary source across the gap is small or negligible because the voltage of the source is too low. 'While the ignition systems, as at present arranged-operate with a primary voltage of 6 or 12 volts. actual experiments have demonstrated that approximately 100 volts are required to produce an appreciable increase in the time interval of the spark. l

According to my present invention. I propose to produce a high-tension discharge b v means of the usual low-tension ,battery or magneto and a transformer or an induction coil. A second source of current having a relatively high voltage, is connected to the secondary circuit anda How of current from this source follows the high-tension dischargv.I across thc spark plug terminals, thusl tem arranged in accordance with my in veution. Fig. 2 is a view. similar to Fig. l. of a modification. i

Referring to Fig. l, a continuoLis-current dynamo-electric machine 1 is illustrated dia grammatically as the details ot' its construc tion form no part of my present invcntiin. The dynamo-electric machine 1 is provided with electrically independcnt armaturc windi'. s indicated at 2 and Il which arc. adapted to generate a relatively high and a relatively low voltage. respectively. The ficld magnet of the generator. which is conimon to the armature windings. embodies a shunt field winding 4- and a series ticld winding 'iwhich are in circuit with the armature 3 and are wound to oppose cach other. The low-voltagc windin; r 3 supplies current to the primary windin; r of a transformer or induction coil which is in circuit with an interruptor T comprising stationary terminals 8 unda movable member f). 'l`hc movable member U is actuated by a cam l() having an operating shaft 1l that is councctcd b v gear wheels 1Q and lil to a distributer 14. condenser l5 is connected in shunt to the terminals i' and S to avoid cxccssive sparking when the interruptor is operated. storage batter)4 1G is also connected to the primary windin, r 6 in parallel with thc gcncrator armature it and supplies current to the primalv winding G under conditions later described.

The circuit of thc generator armature Il is controlledbv an automatic cut-out 1T ha ving a core member 18 surrounded b v two coils 19 and 20 that are connected in series and in shunt. respectively. with the arnuxture Il, The cut-out is provided with an armature Q1 having a pivotal support at 212 and normallyv h'eld upward b v a spring 23. contact mem ber 24 is mounted upon and connected lo the armature .21 and coacts with a stationary contact member 25 to which the coils lil and 2t) are connected in common.

The secondary circuit of the system com prises the high-voltage armature winding 2. the secondary winding 26 of the induction coil, the distributer 14, which may be of the usual construction, und spark plugs 27 havA described. It may be assumed that the gas...

engine, to which the various rotatable members are operatively connected, has been started and that its spee'd is increasing. The circuit of the armature 3 is broken by the cut-out 17, and current is supplied to the rimary winding 6 from the battery 16. he interruptor 7 breaks the primary circuit and a high voltage is thereby induced in the secondary winiing 26 to discharge across the terminals of that spark lug which is connected in circuit by the timer or distributer 14. The high resistance of the spark plug gap is broken down by the high-tension discharge and current from the generator armature 2 follows the discharge. The resultl is to increase the duration of the spark, which is of high heat 'value compared with the spark of the high tension discharge` alone. The duration of the spark and the heat value of the same are important factors in the eilicient operation of internal combustion en gines, and the advantages of my'invention will, therefore, be appreciated by those skilled in the art. y

When the speed of the generator has reached a predetermined value, the coils 19 and 20 are suiiiciently energized to draw the armature 21 downwardly to connect the c0ntact members 24 and 25 and complete the circuit of the armature winding. The generator will then supply current to the primary winding 6 and to the battery 16 for recharging the same. If the generator voltage falls below that of the battery, current tends to flow in the reverse direction through the series coil 19. The coils now oppose each other, and the armature is released to break the lfenerator circuit and thereby prevent the ischarge of the battery 16 through the armature 3.

A moditicatioirof the system above described is shown in Fig. 2, 'in which like numerals are used to designate corresponding parts. One terminal of the battery 16 is grounded, in this form of invention, and that terminal of the armature 2 which is grounded in the system shown in l"ig..1, is connected to the primary circuit between the iiiterrupter 7 an( the primary winding 6.

The operation of the svstem shown in Fig. 2 diifers from that in Fig. l only in that, whenv the high-tension discharge occurs, the voltage of the curient which follows vyill be the sinn of the voltage of the battery 1'6 or the armature 3 and the armature 2. The secondary circuit extends from the ungrounded side of the battery 16 through the primary winding 6, the armature winding 2, secondary Winding 26, distributer 14 and the terminals 28 of the spark plugs 2 7 to ground and back to the battery. When the generator armature 3 is connected in circuit, the voltage of the current flowing iii the secondary circuit is the sum of the voltages of the armatures 2 and 3 which are then in series.

lVhile I have shown'my invention in its preferred fgrm, it is understood' that such chauves may be made as fall within the limits o the ap ended claims. For example, the dynamo-e ectric machine 1 is indicated as being provided with armatures which supply direct current, but it is obvious that the sameeifects may be produced by' means of alternating current armatures if the batter be omitted. x

claim as my invention: i

1. In an ignition system, the combination with a source of current at a relatively high voltage, of a circuit connected to said source and having a gap normally impassable to `sa id current. of means for causing said current to fion' across said gap, said means coinprising a source of current at a relatively low voltage and an induction coil having its secondary winding in said circuit.

2. In van ignition system, the combination with a source of current at a relatively high voltage, of a circuit connected to said source and having a gap normally impassable to said current, and means for causing a discha rgc of current at high voltageacross said gap to cause..tlie passage of, current from sa id source, said means comprising a source of current at a relatively low voltage and an induction coil havin,"r a secondary Winding in circuit with said high voltage source.

3. in an ignition circuit, the combination with a source of current, a primary circuit connected to the source, a secondary circuit that is indue-tively related to the primary circuit and includes'a second source of current having a voltage higher than that of the source of primary current, and a spark plugr having a permanently open gap.

4. ln an ignition system, the combination with a source of current at a Relatively low voltage, of a primary' circuit connected to the source, a source of current at a relatively high voltage,`a secondary circuit that v is india-tively related to the primary circuit and is connected to the Second source of current, and a spark plug connected tosaid secondary circuit.

5. ln an ignition system, the combination' uwith a spark plug having a permanently open gap, and a plurality of sources of current, of means including one of said sources for causing a discharge of current at a high voltage across said gap and for causing aA flow of current having a voltage which is the sum of the voltages of said sources to follow said discharge across said ga 6. In an i nition s stem, the comiiination with a spar plug aving a permanently open gap, and sources o current having relatively high and, low voltages, of means including the low voltage source, for causing a discharge of current at a lngh voltage across said' gap and for causing a fiow of current from said sources in series to follow said discharge across said gap.

7. In an ignition system, the combination with sources of current having relatively high and low voltages, and a spar.'` gap that is normally.v impassable to the current from said sources, of means, including the lowvoltage source, for causing adischarge of current at a high voltage across said gap and for causing a How of current at a voltage which is the sum of the voltages of the said sources to follow said discharge across said ap. 1

8. n an ignition system, the combination with sources of continuous current having relath ely high and low voltages, and a spark gap that is normally impassable to the 'current from said sources, of means including the low-voltage source, for causin `an inductive discharge of current at a hig voltage across said gap and for causing a fiow of continuous current from said sources in series to follow said discharge across said gap. v

9. ln an ignition system, the combination with a source ofcurrent at a relatively high voltage, of a circuit connected to said source and having a gap normally impassable to said current, of means for causing said current to flow across said gap ina single direc- -tion, said means comprising a source of current at a relatively low volta e and an in'- ducton coil having its secon ary winding f in said circuit.

l0. In an ignition system, the combination with a source of current at a relatively high voltage, of a circuit connected to said source and having a gap normally impassable to said current, and means for causing a discharge of current at high voltage across said ga i to cause the passage of current from sai source in a single direction,

said means comprising a source of current at a relatively low voltage and an induction coil havin a secondary winding in circuit with saidthigh voltage source.

l1. In an electrical system for motor veY hicles, the combination with two sources of current, of a battery connected to the first source of current and adapted to be charged thereby, an induction coil having its primary winding connected to said battery and to said lirst source, the second source of current being of relatively higher voltage than the source that charges the battery, a circuit including the secoucLsourf-e of current and also the secondary winding of said induction coil and having a gap normally impassable to the current from said second source, and an interrupter in the primary circult of said induction coil for causing a discharge of current across said gap,

whereby said gap will be rendered passable.

to current from the second source.

12. 1n un electrical system for motor vehicles, the combination with a dynamoelectric machine comprising two windings for generating currents oi different voltages, of a battery connected to the winding generating the Ylower voltage and adapted yto be charged with current therefrom, an induction coil having its primary winding connected to said battery and to said low voltage winding, a circuit including the winding that generates the higher voltage and also including the secondary winding of said induction coil and having a gap normally impassalle to the current from said high-voltage winding, and means for interrupting th'e primarv circuit. of said 'indiution coil to cause a discharge of cur rent across said gap, whereby said gap will be rendered passable to current from the hifrh-voltage winding.

n testimony whereof l have hereunto subscribed my name this 31st day ot May,

' n FRANK CONRAD. Witnesses B. B. l-lmns, C. E. VVILsoN.y 

